Thomas Samuel Kuhn (1922-1996) was a historian and philosopher of science whose extremely popular book, The Structure of Scientific Revolutions, has had a profound and enduring impact on the philosophy of science. In Structure, Kuhn proposed a model of scientific theory change according to which science advances by revolutionary displacement of the theoretical structures he called "paradigms". Kuhn's account of such scientific revolutions was controversial because it appeared to suggest that such theoretical change cannot be made on a rational basis due to the incommensurability of alternative paradigms. It also contains a challenge to the scientific realist view that scientific progress constitutes a continual progression toward the truth about the world. Kuhn continued to develop his ideas in later publications in a way which led to a moderation of his views about theory choice, though he retained his anti-realist view. He later claimed that science is governed by a set of epistemic values that provide the rationale for theory choice, though these values do not constitute an algorithm for theory choice. He also developed a refined view of the incommensurability thesis, according to which there is a translation failure between a narrow group of interdefined terms within competing theories, but this untranslatability does not prevent mutual understanding between advocates of rival theories. Kuhn is best known for his model of scientific theory change and some of the controversial philosophical ideas associated with this model. But he was also the author of several major works in the history of physics.

In thts paper I argue that Kuhn's analysis of the role played by `exemplars' in normal science should be considered one of his most important contributions to the Philosophy of Science. The paper makes a detailed analysis of the relationship between the various elements of a 'disciplinary matrix´— empirical generalizations, models and exemplars — starting with Kuhn's views as exposed in various of his books and papers. Kuhn's analysis is investigated in the context of the discussions, in the 50s and (...) 60s, about the notion of `model' in the so called `received view' of the structure of scientific theories. I refer also to the critics of logical empiricism at this time, that were concerned with analogical models and inspired by Campbell's studies on the dynamics of theories. I argue also that Polanyi's notion of 'tacit knowledge' and some of his discussions of the role played by analogies in mathematics have been an important influence on Kuhn. The paper indicates, furthermore, how Kuhn's intuitions concerning exemplars are being developped in the present, by plilosophers of science like Thagard, Paul Churchland and Giere, that adopt a `cognitivist´ stance towards scientific reasoning. (shrink)

: In response to a charge of subjectivism, Kuhn in his Postscript emphasizes the importance of "values" (accuracy, simplicity, explanatory power, etc) that are shared by scientists generally. However, Kuhn adds, these values are applied differently by different scientists. By employing a comparison with partially subjective views of Carnap on confirming evidence, this paper raises questions about Kuhn's position on values by considering ways it might be interpreted as subjective and ways it may not.

The tu quoque argument is the argument that since in the end rationalism rests on an irrational choice of and commitment to rationality, rationalism is as irrational as any other commitment. Popper's and Polanyi's philosophies of science both accept the argument, and have on that account many similarities; yet Popper manages to remain a rationalist whereas Polanyi decided for an irrationalist version of rationalism. This is more marked in works of their respective followers, W. W. Bartley III and Thomas S. (...) Kuhn. Bartley declares the rationalist's very openness to criticism open to criticism, in the hope of rendering Popper's critical rationalism quite comprehensive. Kuhn makes rationality depend on the existence of an accepted model for scientific research (paradigm), thus rendering Polanyi's view of the authority of scientific leadership a sine qua non for scientific progress. The question raised here is, in what sense is a rationalist committed to his rationality, or an irrationalist to his specific axiom ? The tradition views only the life?long commitment as real. Viewing rationality as experimental open?mindedness, we may consider a rationalist unable to retreat into any life?long commitment ? even commitment to science. In this way the logic of the tu quoque argument is made irrelevant: anyone able to face the choice between rationality and commitment is already beyond such a choice; it is one thing to be still naïve and another ? and paradoxical ? thing to return to one's naïveté. (shrink)

In this article, I discuss Gadamer's hermeneutic account of understanding as an alternative to Kuhn's incommensurability thesis. After a brief account of Kuhn's aesthetic account and arguments against it, I argue that the linguistic account faces a paradox that results from Kuhn's objectivist account of understanding, and his lack of historical reflexivity. The statement 'Languages are incommensurable' is not a unique view of language, and is thus subject to contest by incommensurable readings. Resolving the paradox requires an account of incommensurability (...) that is self-referentially consistent, open-ended, and historically reflexive whereby we recognize that our very interest in incommensurability is historically conditioned. By meeting these conditions, Gadamer's account of historical understanding offers a middle ground between two extremes: on the one side is the claim that understanding involves becoming a native of an incommensurable language, and on the other side is the rejection of the prospect of understanding a contextually removed language altogether. Gadamer is discussed as a mediator between Kuhn's epistemic and historical projects, and thus paves the way for a new hermeneutics of science. The notions of traditional horizon, historically effected consciousness, the universality of interpretation, alienation, dialogical openness, and the fusion of horizons are also discussed. (shrink)

Kuhn's distinction of within- and between-paradigm thinking can be extended using his notion of a problem-field. Hull's notion of populational variation applies within paradigms; his type specimen approach allows one to analyze disagreement and identify the problem-field. Categories of questions or problem frames can also partition debate, establishing interparadigm variation. A case where multiple simultaneous paradigms compete highlights the role of empirical domains. The Ox-Phos Controversy in bioenergetics (1961-1977) serves as a case study. Conclusions are framed as strategies for scientists.

In a previous article we have shown that Kuhn's theory of concepts is independently supported by recent research in cognitive psychology. In this paper we propose a cognitive re?reading of Kuhn's cyclical model of scientific revolutions: all of the important features of the model may now be seen as consequences of a more fundamental account of the nature of concepts and their dynamics. We begin by examining incommensurability, the central theme of Kuhn's theory of scientific revolutions, according to two different (...) cognitive models of concept representation. We provide new support for Kuhn ?s mature views that incommensurability can be caused by changes in only a few concepts, that even incommensurable conceptual systems can be rationally compared, and that scientific change of the most radical sort?the type labeled revolutionary in earlier studies?does not have to occur holistically and abruptly, but can be achieved by a historically more plausible accumulation of smaller changes. We go on to suggest that the parallel accounts of concepts found in Kuhn and in cognitive science lead to a new understanding of the nature of normal science, of the transition from normal science to crisis, and of scientific revolutions. The same account enables us to understand how scientific communities split to create groups supporting new paradigms, and to resolve various outstanding problems. In particular, we can identify the kind of change needed to create a revolution rather precisely. This new analysis also suggests reasons for the unidirectionality of scientific change. (shrink)

This paper focuses on Thomas S. Kuhn's work on taxonomic concepts and how it relates to empirical work from the cognitive sciences on categorization and conceptual development. I shall first review the basic features of Kuhn's family resemblance account and compare to work from the cognitive sciences. I shall then show how Kuhn's account can be extended to cover the development of new taxonomies in science, and I shall illustrate by a detailed case study that Kuhn himself mentioned only briefly (...) in his own work, namely the discovery of X-rays and radioactivity. (shrink)

In his analysis of “the essential tension between tradition and innovation” Thomas S. Kuhn focused on the apparent paradox that, on the one hand, normal research is a highly convergent activity based upon a settled consensus, but, on the other hand, the ultimate effect of this tradition-bound work has invariably been to change the tradition. Kuhn argued that, on the one hand, without the possibility of divergent thought, fundamental innovation would be precluded. On the other hand, without a strong emphasis (...) on convergent thought, science would become a mess created by continuous theory changes and scientific progress would again be precluded. On Kuhn’s view, both convergent and divergent thought are therefore equally necessary for the progress of science. In this paper, I shall argue that a similar fundamental tension exists between the demands we see for novel insights of an interdisciplinary nature and the need for established intellectual doctrines founded in the classical disciplines. First, I shall revisit Kuhn’s analysis of the essential tension between tradition and innovation. Next, I shall argue that the tension inherent in interdisciplinary research between, on the one hand, intellectual independence and critical scrutiny and, on the other hand, epistemic dependence and trust is a complement to Kuhn’s essential tension within mono-disciplinary science between convergent and divergent thought. (shrink)

Thomas Kuhn's Structure of Scientific Revolutions became the most widely read book about science in the twentieth century. His terms 'paradigm' and 'scientific revolution' entered everyday speech, but they remain controversial. In the second half of the twentieth century, the new field of cognitive science combined empirical psychology, computer science, and neuroscience. In this book, the recent theories of concepts developed by cognitive scientists are used to evaluate and extend Kuhn's most influential ideas. Based on case studies of the Copernican (...) revolution, the discovery of nuclear fission, and an elaboration of Kuhn's famous 'ducks and geese' example of concept learning, the volume offers new accounts of the nature of normal and revolutionary science, the function of anomalies, and the nature of incommensurability. (shrink)

It is a commonly raised argument against thefamily resemblance account of concepts that, on thisaccount, there is no limit to a concept's extension.An account of family resemblance which attempts toprovide a solution to this problem by including bothsimilarity among instances and dissimilarity tonon-instances has been developed by the philosopher ofscience Thomas Kuhn. Similar solutions have beenhinted at in the literature on family resemblanceconcepts, but the solution has never received adetailed investigation. I shall provide areconstruction of Kuhn's theory and argue that (...) hissolution necessitates a developmental perspective withbuilds on both the transmission of taxonomies betweengenerations and a progressive development throughhistory. (shrink)

Drawing on the results of modem psychology and cognitive science we suggest that the traditional theory of concepts is no longer tenable, and that the alternative account proposed by Kuhn may now be seen to have independent empirical support quite apart from its success as part of an account of scientific change. We suggest that these mechanisms can also be understood as special cases of general cognitive structures revealed by cognitive science. Against this background, incommensurability is not an insurmountable obstacle (...) to accepting Kuhn's position, as many philosophers of science still believe. Rather it becomes a natural consequence of cognitive structures that appear in all human beings. (shrink)

In this paper I address some of the problems that the historical development of science poses for a realist and discuss whether a realist construal of scientific activity is conducive to historiographical practice. First, I discuss, by means of historical examples, Ian Hacking's defense of entity realism. Second, I try to show, drawing on Kuhn's recent work on incommensurability, that the realism problem is relevant to historiography and that a realist position entails a particular historiographical strategy, which faces problems. Finally, (...) I suggest that for historiographical purposes an agnostic attitude with respect to scientific theories and unobservable entities is the most appropriate. (shrink)

I argue that Plato’s use of thought experiments anticipate many of the themes discussed by Thomas S. Kuhn’s classic essay, “A Function for Thought Experiments.” Kuhn’s concern is that thought experiments satisfy the condition of verisimilitude. That is, thought experiments must not be conducted merely to alter the conceptual apparatus of the scientist regarding the phenomenon explored, but rather to alter the scientist’s conceptual apparatus for the sake of altering his actions (i.e., practical rationality). Plato, too, is quite concerned with (...) getting interlocutors to appreciate that theory not be separated from practice, and that theory is necessary for the process of effective decision making. Each of the interlocutors presented in the Republic, Apology and Alcibiades Minor are confrontedwith a thought experiment that is designed to effect how they choose to live. Although the three dialogues I discuss illustrate the Kuhnian admonishment against separating theory form practice, many other dialogues in the Platonic corpus echo Kuhn’s concerns. (shrink)

Thirty years after its publication, Thomas Kuhn's The Structure of Scientific Revolutions is still the source of much discussion in economics. Its rel-ativistic tone has often been used to fuel the claims of dissident traditions against the prevailing orthodoxy, or at least to plead the case for intellectual pluralism . Through his arguments regarding the incommensurability of different theoretical approaches to a particular subject, Kuhn's work has allowed many to argue that dissident traditions are just as legitimate as orthodoxy for (...) analyzing a subject, since there is no objective or independent means of arbitrating between them. This has caused an opposing response by those more supportive of the prevailing theoretical approach to economics. The latter have tried to find a defense to relativist challenges in more “rational” philosophies of science, such as that of Lakatos. (shrink)

Central to Kuhn's notion of incommensurability are the ideas of meaning variance and lexicon, and the impossibility of translation of terms across different theories. Such a notion of incommensurability is based on a particular understanding of what a scientific language is. In this paper we first attempt to understand this notion of scientific language in the context of incommensurability. We consider the consequences of the essential multisemiotic character of scientific theories and show how this leads to even a single theory (...) being potentially 'internally incommensurable'. We then discuss Kuhn's lexicon-based approach to incommensurability and the problems associated with it. Finally we argue that this approach by Kuhn has interesting overlaps with the problem of meaning associated with multisemiosis, particularly the challenge of understanding the process of symbolization in scientific theories. (shrink)

Summary In a case study Kuhn's morphology of scientific revolutions is put to the test in confronting it with the contemporary developments in physics. It is shown in detail, that Kuhn's scheme is not compatible with the situation in physics today.

Summary Critics have said that Kuhn's account of scientific revolutions represents them as subjective and irrational processes, in which mystical conversions and community pressures rather than good reasons determine choices between theories. Kuhn rejects the charge, insisting that there is partial communication among proponents of competing paradigm candidates and their arguments are rational though not coercive. The critics reply that in fact Kuhn's position entails total non-communication and irrationality. A Kuhnian account of partial communication is thus necessary. Kuhn's attempt to (...) give one, based on the notion that the good reasons advanced in paradigm debates function asvalues, fails. But a more satisfactory account can be given if it is recognized that paradigm-debaters will, in one or both of two ways, share paradigmsother than the ones at issue. Further, Kuhn's position both should and can accommodate a notion of theory reduction; his unqualified rejection of reduction is an unnecessary weakness, even apart from questions about the rationality of revolutions. The paper concludes with a brief examination of the contrast between Kuhn's and Feyerabend's strategies for the advancement of science. (shrink)

Thirty years after the publication of Thomas Kuhn’s The Structure of Scientific Revolutions, sharp disagreement persists concerning the implications of Kuhn’s "historicist" challenge to empiricism. I discuss the historicist movement over the past thirty years, and the extent to which the discourse between two branches of the historical school has been influenced by tacit assumptions shared with Rudolf Carnap’s empiricism. I begin with an examination of Carnap’s logicism --his logic of science-- and his 1960 correspondence with Kuhn. I focus on (...) problems in the analysis applied to the unit of metascientific study or appraisal, arguing for a reassessment of historicist treatment of the internal/external distinction and historiographic meta-methodology. The critique of objectivism and relativism that eventuates from this re-assessment is a double-edged blade, undercutting both objectivist and relativist treatments of cognitive evaluation and scientific change. I use it to cut across an otherwise diverse group of historicist-influenced writers, including Imre Lakatos, Larry Laudan, H. M. Collins, Stephen Stich. I. Introduction.. (shrink)

Discusses the use by several philosophers of the book "The Structure of Scientific Revolutions," by philosopher Thomas S. Kuhn, as an intellectual source for attacking the sociology of science proposed by Robert K. Merton and his students. Assertion by Kuhn that the philosophers attacking Merton had misconstructed his ideas; Sociology of Kuhnian sociology of science established by Steve Fuller.

This article argues that the limited influence of Ludwik Fleck's ideas on philosophy of science is due not only to their indirect dissemination by way of Thomas Kuhn, but also to an incommensurability between the standard conceptual framework of history and philosophy of science and Fleck's own more integratedly historico-social and praxis-oriented approach to understanding the evolution of scientific discovery. What Kuhn named "paradigm" offers a periphrastic rendering or oblique translation of Fleck's Denkstil/Denkkollektiv , a derivation that may also account (...) for the lability of the term "paradigm". This was due not to Kuhn's unwillingness to credit Fleck but rather to the cold war political circumstances surrounding the writing of The Structure of Scientific Revolutions . Following a discussion of Fleck's anatomical allusions, I include a brief discussion of Aristotle (on menstruation and darkened mirrors) and conclude with a reference to the productivity of error in Mach and Nietzsche. (shrink)

Thomas Kuhn is a rarity. Widely regarded as one of the most influential theorists of the physical sciences, he has also, largely through his concept of the ‘paradigm’, had a sustained effect on the social sciences and education. His classic The Structure of Scientific Revolutions is read and cited by scholars in an astonishing range of disciplines, in part due to its acquired association with progressive social research and practice. This article takes issue with Kuhn’s conceptions of science and its (...) translation into educational practice, and suggests that they do not deserve the warm embrace they have received. It is argued that Kuhn’s popularity among progressive thinkers is somewhat ironic, since his portrayal of ‘normal science education’ is inherently indoctrinatory, presenting insurmountable barriers to acceptance as part of a liberal educational philosophy. (shrink)

We present a reconstruction of so-called classical, formal or Mendelian genetics using a notation which we believe is more legible than that of earlier accounts, and lends itself easily to computer implementation, for instance in PROLOG. By drawing from, and emending, earlier work of Balzer and Dawe (1986,1997), the present account presents the three most important lines of development of classical genetics: the so-called Mendel's laws, linkage genetics and gene mapping, in the form of a theory-net. This shows that the (...) set theoretic representation format used in the structuralist approach to the philosophy of science also applies to the domain of genetic theories. There construction is intended to lend more clarity to theme thodological, philosophical and didactical discussions of the foundations of genetics, and on the other hand to defend a formally, logically minded view of theories which seems to have become contested through the work of Feyerabend, Kuhn and Kitcher. (shrink)

: This paper continues my application of theories of concepts developed in cognitive psychology to clarify issues in Kuhn's mature account of scientific change. I argue that incommensurability is typically neither global nor total, and that the corresponding form of scientific change occurs incrementally. Incommensurability can now be seen as a local phenomenon restricted to particular points in a conceptual framework represented by a set of nodes. The unaffected parts in the framework constitute the basis for continued communication between the (...) communities supporting alternative structures. The importance of a node is a measure of the severity of incommensurability introduced by replacing it. Such replacements occur incrementally so that changes like that from the conceptual structure of Aristotelian celestial physics to the conceptual structure of Newtonian celestial physics occur in small stages over time, and for each change it is in principle possible to identify the arguments and evidence that led historical actors to make the revisions. Thus the process of scientific change is a rational one, even when its beginning and end points are incommensurable conceptual structures. It is also apparent, from a detailed examination of the conceptual structure of astronomy at the time of Copernicus, thatthe kind of conceptual difficulty identified as incommensurability may occur within a single scientific tradition as well as between two rival traditions. (shrink)

In focusing their view on Kuhn, Robert Veatch and William Stempsey ignore alternative sources of insight from other voices that could help move us beyond incommensurability. Richard Rorty and Helen Longino, for example, offer another view of science and objectivity with constructive insight for the practice of science and medicine. Keywords: positivism, relativism, scientific knowledge, incommensurability, Kuhn, Rorty, Longino CiteULike Connotea Del.icio.us What's this?

In a thought experiment we want to test how the emergence of adult neural stem cells could constitute an example for a scientific revolution in the sense of Thomas Kuhn. In his major work, The structure of scientific revolutions, 3rd edn, University of Chicago Press, Chicago (Kuhn 1996), the philosopher of science, Thomas Kuhn, states that scientific progress is not a cumulative process, but new theories appear by a rather revolutionary sequence of events. Kuhn built his theory on landmark events (...) taken from chemistry and physics, lacking examples from biology. Beginning with Ramon y Cajalâs famous quote, no new neurons after birth , from the early years of the twentieth century, and Reynolds and Weissâs conflicting finding in 1992 of adult neural stem cells giving rise to new neurons, we will test how the finding of neural stem cells in the adult brain matches with Kuhnâs theory. The pivotal problem of defining a paradigm will be our main focus, since the emergence of adult neural stem cells has been acclaimed by the scientific community as the rebuttal of Ramon y Cajalâs paradigm. (shrink)

Maurice Merleau-Ponty’s later philosophy is not a simple revision of the themes of Phenomenology of Perception. It is a radical change of the kind Thomas Kuhn found in the history of science which involves: (1) a persistent anomaly, (2) the formation of new assumptions and (3) the creation of a new vocabulary. This paper concentrates on the problem Merleau-Ponty had with the tacit cogito and shows how he broke the tension it caused by changing the paradigm of his philosophy. It (...) also examines that new philosophy to see whether it is more compatible with Christianity as some commentators have claimed. (shrink)

Thomas Kuhn was undoubtedly the strongest influence on the philosophy of science in the last third of the twentieth century. Yet today, at the beginning of the twenty-first century it is unclear what his legacy really is. In the philosophy of science there is no characteristically Kuhnian school. This could be because we are all Kuhnians now. But it might also be because Kuhn’s thought, although revolutionary in its time, has since been superseded. In a sense both may be true. (...) We are all Copernicans—yet almost everything Copernicus believed we now disbelieve. In this paper I shall examine the development of Kuhn’s thought in connection with changes in the philosophy of science during the second half of the twentieth century. Now that philosophy in general, philosophy of science in particular, is in a post-positivist era, we all share Kuhn’s rejection of positivism. But we do not, for the most part, share Kuhn’s belief in incommensurability, or his scepticism about truth and objective knowledge. Just as in Copernicus’ case, Kuhn initiated a revolution that went far beyond what he himself envisaged or even properly understood. (shrink)

I defend my view that scientific progress is constituted by the accumulation of knowledge against a challenge from Rowbottom in favour of the semantic view that it is only truth that is relevant to progress.

The Structure of Scientific Revolutions is one of the most cited academic books of all time. His contribution to the philosophy science marked not only a break with several key positivist doctrines but also inaugurated a new style of philosophy of science that brought it much closer to the history of science. His account of the development of science held that science enjoys periods of stable growth punctuated by revisionary revolutions, to which he added the controversial ‘incommensurability thesis’, that theories (...) from differing periods suffer from certain deep kinds of failure of comparability. (shrink)

In this paper I argue that we can understand incommensurability in a naturalistic, psychological manner. Cognitive habits can be acquired and so differ between individuals. Drawing on psychological work concerning analogical thinking and thinking with schemata, I argue that incommensurability arises between individuals with different cognitive habits and between groups with different shared cognitive habits.

I argue that the naturalism of Thomas Kuhn's "The Structure of Scientific Revolutions," which he himself later ignored, is worthy of rehabilitation. A naturalistic conception of paradigms is ripe for development with the tools of cognitive science. As a consequence a naturalistic understanding of world-change and incommensurability is also viable.

Kuhn's incommensurability thesis seems to challenge scientific realism. One response to that challenge is to focus on the continuity of reference. The casual theory of reference in particular seems to offer the possibility of continuity of reference that woud provide a basis for the sort of comparability between theories that the realist requires. In "Dubbing and Redubbing: the vulnerability of rigid designation" Kuhn attacks the causal theory and the essentialism to which is is related. Kuhn's view is defended by Rupert (...) Read and Wes Sharrock. In this paper I examine the arguments presented by Kaul, Read and Sharrock and show that they provide no reason to doubt either the causal theory or essentialism. (shrink)

I argue that the naturalism of Thomas Kuhn’s The Structure of Scientiﬁc Revolutions, which he himself later ignored, is worthy of rehabilitation. A naturalistic conception of paradigms is ripe for development with the tools of cognitive science. As a consequence a naturalistic understanding of world-change and incommensurability is also viable.

I defend against criticism the following claims concening Thomas Kuhn: (i) there is a strong naturalist streak in The structure of scientific revolutions, whereby Kuhn used the results of a posteriori enquiry in addressing philosophical questions; (ii) as Kuhn's career as a philosopher of science developed he tended to drop the naturalistic elements and to replace them with more traditionally philosophical a prior approaches; (iii) at the same there is a significant residue of positivist thought in Kuhm, which Kuhn did (...) not recognise as such; (iv) the naturalist elements referred to in (i) are the most original and fruitful elements of Kuhn's thinking; (v) the positivistic elements referred to in (iii) vitiated his thought and acted as factors in preventing Kuhn from developing the naturalistic elemtns and from following the path taken by much subsequent philosophy of science. Preston presents an alternative reading of Kuhn which emphasizes the Wittgensteinian elements in Kuhn. I argue that this alternative view is, descriptively, poorly supported by the textual evidence and the facts of the history of philosophy of science in the twentieth century. I provide some defence of the naturalistic approach and related themes. (shrink)

In this paper I draw a connection between Kuhn and the empiricist legacy, specifically between his thesis of incommensurability, in particular in its later taxonomic form, and van Fraassen's constructive empiricism. I show that if it is the case the empirically equivalent but genuinely distinct theories do exist, then we can expect such theories to be taxonomically incommensurable. I link this to Hacking's claim that Kuhn was a nominalist. I also argue that Kuhn and van Fraassen do not differ as (...) much as might be thought as regards the claim that observation is theory laden. (shrink)

Why, despite his enormous inﬂuence in the latter part of the twentieth century, has Kuhn left no distinctively Kuhnian legacy? I argue that this is because the development of Kuhn’s own thought was in a direction opposite to that of the mainstream of the philosophy of science. In the 1970s and 1980s the philosophy of science took on board the lessons of externalism as regards reference and knowledge, and became more sympathetic to a naturalistic approach to philosophical problems. Kuhn, on (...) the other hand, started out with a strong naturalistic streak, employing non-philosophical disciplines, primarily psychology, in order to build his accounts of scientiﬁc change and the nature of observation and scientiﬁc thought. But by the 1970s Kuhn’s work had taken on a much more purely philosophical, a priori, tone. His explanation of incommensurability moved from a psychological explanation to one embedded in the philosophy of language. Increasingly he gave his outlook a Kantian gloss. I suggest, nonetheless, that Kuhn’s most valuable contribution is to be found in The Structure of Scientiﬁc Revolutions and not in his later work, and that the naturalistic direction of the former has important links with connectionist research in cognitive science that deserve further study.  2002 Elsevier Science Ltd. All rights reserved. (shrink)